Khan.scratchpad.disable(); Tiffany sells magazine subscriptions and earns $$10$ for every new subscriber she signs up. Tiffany also earns a $$38$ weekly bonus regardless of how many magazine subscriptions she sells. If Tiffany wants to earn at least $$75$ this week, what is the minimum number of subscriptions she needs to sell?
Solution: To solve this, let's set up an expression to show how much money Tiffany will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Tiffany wants to make at least $$75$ this week, we can turn this into an inequality. Amount earned this week $\geq $75$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $75$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $10 + $38 \geq $75$ $ x \cdot $10 \geq $75 - $38 $ $ x \cdot $10 \geq $37 $ $x \geq \dfrac{37}{10} \approx 3.70$ Since Tiffany cannot sell parts of subscriptions, we round $3.70$ up to $4$ Tiffany must sell at least 4 subscriptions this week.